In some of hydrogen production apparatuses as described in Technical Field above, a low temperature shift unit and a preferential oxidation unit for reducing a carbon monoxide concentration in a reformed gas are provided at a stage following a reforming unit for subjecting a raw fuel and steam to a reforming reaction to generate a reformed gas. The reforming unit is heated with a burner in many cases because a reforming reaction is an endothermic reaction at high temperatures. Therefore, a high-temperature reformed gas is exhausted from an outlet of the reforming unit, and an exhaust gas from the burner passes in the vicinity of the outlet of the reforming unit. The high-temperature reformed gas exhausted from the outlet of the reforming unit is introduced to the low temperature shift unit and the preferential oxidation unit after being cooled by a heat exchange unit or the like in many cases because a shift reaction and a preferential oxidation reaction are performed at temperatures lower than the reforming reaction due to catalyst reaction conditions. Furthermore, the exhaust gas from the burner is cooled with raw water or the like in the heat exchange unit, without coming into direct contact with the low temperature shift unit and the preferential oxidation unit, and exhausted to the outside of the hydrogen production apparatus in many cases. Therefore, the low temperature shift unit and the preferential oxidation unit are sometimes provided with an electrical heater for increasing the temperature during start-up, for the purpose of quickly increasing the temperature of the low temperature shift unit and the preferential oxidation unit and reducing the start-up time when each inside catalyst is heated to a usable temperature during start-up of the hydrogen production apparatus (see, for example, Patent Literatures 1 and 2).